FR-A-2 407 258 (Rhone-Poulenc) discloses fuel compositions comprising a motor fuel and at least one alkylpolyglycol acetic acid amide having the formula: ##STR2## wherein R represents a saturated or unsaturated C.sub.8-20, preferably C.sub.12-18, aliphatic radical, R' represents hydrogen or a saturated or unsaturated aliphatic radical of at least 3, preferably 4 to 18, carbon atoms, and R" represents a saturated or unsaturated aliphatic radical of at least 3, preferably 4 to 18, carbon atoms. In the examples, there are described additives of the above formula in the form (1) of the N,N-dibutylamide of the acid derived from a 45:55 mixture of polyethoxylated cetyl and oleyl alcohols (C.sub.16 saturated and C.sub.18 unsaturated alcohols) wherein n is 6.3, (2) of the N-dodecylamide of the acid derived from a 75:25 mixture of polyethoxylated dodecyl and tetradecyl alcohols wherein n is 4.5 and (3) of the N,N-dibutylamide of the acid from which (2) is derived. The amides are said to impart improved detergency, anti-corrosion, anti-pollution and anti-icing properties to hydrocarbon fuels.